Snödjupsfördelningens och snödensitetens påverkan på palsdegradationen i Vissatvuopmi, Saarikoski, Lappland

Abstract

Palsas are mounds of permafrost and or peat/mineralsoil that occurs in areas with discontinuos permafrost. Palsas has a natural development but in recent decades in step with the global warming, an increased degradation has occurred, something that does not seem to be related with the natural development of palsas. In addition to global warming, numerous local factors are assumed to have an impact on the formation of palsa such as snow depth and snow density. There are few studies that have analyzed this more closely. The purpose of this study has therefore been to research how the distribution of snow depth and snow density on and around a palsa have an impact on palsa degradation. Measurements of snow depth and snow density was made on two different types of palsa, a dome palsa and a palsa plateu, located in a palsablog complex in Vissatvuopmi. Wind data from nearby metrological station was used to study how the wind affects the snow depth and snow density on and around a palsa. The snow depth and snow density show a good conformation with the degradation of palsa, where the snow is deepest and has the lowest density, the degradation has occurred the most. Though, there is also a high snow density in a small area that has been significantly degraded, which seems to have a relation with wind direction. In general, high snow density occurs where the surfaces are flat and exposed to wind. A clear relation can be seen between snow depth distribution, snow density distribution and palsa degradation, which points out, in addition to global warming, there are local factors that have an impact on degradation of palsa. The relation between snow depth, snow density and palsa degradation confirms that local factors have an impact on palsa degradation.